1. Field of the Invention
The present invention relates in general to wireless transceivers integrated with a Global Positioning System (GPS) receiver, and in particular to a method and apparatus for reducing GPS receiver jamming during transmission by the wireless transceiver.
2. Description of the Related Art
Wireless communications systems, including cellular telephony, Personal Communication System (PCS) devices, Personal Data Assistants (PDAs), and other wireless handsets and devices, has become commonplace. The use of such devices to provide voice, data, and other services, such as internet access, has provided many conveniences to wireless system users.
Currently, designers are integrating Global Positioning System (GPS) technology into wireless devices and other wireless transceivers. The GPS system transmits at 1.575 GHz, and the cellular and PCS systems transmit at 900 MHz and 1.9 GHz, respectively. Inherent in a device that combines GPS reception and wireless transmission circuitry, which circuitry includes an antenna, undesired electromagnetic coupling between the transmitter of the wireless transceiver and the GPS receiver w,ill occur. Since cellular devices (handsets) are typically small in size, it is desirable to have a device that can share an antenna for use by both the GPS receiver and the wireless transceiver, if this is possible without deleterious performance effects on either system.
Since the cellular and PCS transmitted signals are extremely strong signals relative to the GPS received signals, and these strong signals or their harmonics can degrade the sensitivity of the GPS receiver during wireless transceiver transmission, unless filtering or other methods are employed to reject the interfering or jamming signal As such, the reliability and operation of GPS receivers that are used in conjunction with cellular handsets is degraded.
It can be seen, then, that there is a need in the art for a method of reducing the effects of wireless transmissions on proximate GPS receivers. It can also be seen that there is a need in the art for an apparatus that can reduce the effects of wireless transmissions on GPS receivers. It can also be seen that there is a need in the art for a method and apparatus that can allow GPS receivers and wireless transmitters to share a common antenna.